08/04/2009 - 22:00

Climate claims need critical evaluation

08/04/2009 - 22:00


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Climate change provokes passionate arguments from both sides, but does the evidence support claims of humans’ role?

MANY have branded me a 'climate change sceptic', usually employing a derogatory tone such as they might use when describing one who has committed the most heinous of crimes.

However, while I am proud to be sceptical by nature - my natural scepticism honed by a long career as a research scientist, then heightened further in the bearpit of federal politics - I must say the critics are downright wrong in this charge.

Climate change is a reality - and it has been throughout the history of our planet. Scepticism doesn't come into it.

Rather, the label of climate change sceptic has become a slur for anyone - and there are many of us - who dares to challenge the prevailing belief that humans are responsible for all adverse developments on earth.

It is part of the same dogma which holds that industry is bad and that mining uranium is effectively little different to launching nuclear weapons.

What I am sceptical about is the claim that human activity is driving climate change. I am also sceptical about the claim the climate has been significantly warming in recent years, and that this justfies projections of dramatic warming for the century ahead, and beyond.

We have read all of the doom-laden prognostications.

For example, consider the following quote: "The evidence in support of these predictions has now begun to accumulate so massively that meteorologists are hard-pressed to keep up with it ... During the same time, the average temperature around the equator has risen by a fraction of a degree - a fraction that in some areas can mean drought and desolation"

The interesting thing about this quote is not the tone, for we have become used to the end-of-the world scenarios. We have also become used to the absolute certainty expressed in predictions of the devastation to come, and the certainty in the predictions. No, the interesting thing is that the above words came from Newsweek in the edition of April 28 1975, in an article entitled 'The Cooling World'.

Indeed, some of the scientists predicting an oncoming ice age then are the same scientists now leading the charge on supposed global warming.

Scientists such as Stephen Schneider, who has stated: "So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This 'double ethical bind' we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest."

Staggering, when these self same scientists insist that what they are saying on climate is the complete truth.

Just how accurate are the projections or predictions of the Intergovernmental Panel on Climate Change (IPCC)? How certain is the science? Most of us are well aware of the huge problems associated with the emissions trading scheme (ETS) as proposed by the federal government.

The ETS, with its implications for industry, and the economy as a whole, is obviously of great importance, but the science of the matter is something that also requires critical evaluation.

The underlying "consensus science" propounded by the IPCC is taken as a given, with anyone daring to question the received wisdom branded a heretic, denier or, God forbid, sceptic (though scepticism in science is actually a good thing, yet you would not think so, given the rhetoric).

Given that climate is variable - it always has changed and always will change - the question then becomes one of trying to ascertain if humans are having an effect on climate, and if so, to what extent.

The evidence that carbon dioxide is causing warming should, according to all the models, result in a fingerprint hotspot in the upper troposphere in the tropics. This is one of the factors highlighted in the IPCC 4th Assessment Report.

Problematically, the hotspot is nowhere to be seen, despite a lot of effort having been expended searching for it. So, given the IPCC's own scientific evidence, the theory that carbon dioxide has caused warming remains just that - a theory that has not been proven.

Next, the data on global average temperature changes. There have been questions asked about the location of thermometers (some are placed in places affected by the "urban heat island") and statistical processes used to arrive at these averages.

Despite this, the trend in the last century has been heating to around 1945, cooling to around 1975, heating to 1998, and cooling since then. In fact, according to the Hadley Centre (most used by the IPCC) the rate of cooling since January 2001 is a little over one degree centigrade per century - a far cry from the five degrees of heating projected in some of the worst scenarios by the end of the century.

There are a few interesting things to note about this temperature record. First, the warming of the first half of the century is ascribed to natural causes, and the cooling due to aerosols (or small particulates in the atmosphere). The basis of human-induced climate change is thus premised on the 20-year period from around 1975 to 1998.

Second, the cooling since then is unexplained. In fact, according to all the models produced by the IPCC (including a scenario where carbon dioxide is held constant at year 2000 levels), temperatures should have increased this century, certainly not decreased.

There is an old computer adage, garbage in, garbage out. In the case with global warming computer models, however, it has become garbage in, gospel out.

Around the world, there are 3,000 Argo buoys measuring ocean temperature. The data shows that global ocean temperatures have decreased since 2003, once again, in conflict with model projections.

Many have heard about increasing temperatures and decreasing sea ice area in the Arctic, but how often have you heard about Antarctic temperatures decreasing, and increasing Antarctic sea ice area?

Now there is an inconvenient truth, and it is no wonder that this has not been widely reported. The media, for the most part, has been reluctant to challenge the prevailing popular opinion - after all, for most of their audience, and many of their advertisers, human-induced global warming is an article of faith.

It is these inconsistencies that make me so sceptical about the many claims on global warming, and the role of human's in climate change. Take a closer look at the supposed evidence used in support of these claims and you might find yourself also feeling sceptical.

n Dennis Jensen is the federal member for Tangney, and was previously a research scientist with CSIRO and the Defence Science and Technology Organisation.


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